That’s a great question. One I can’t answer without sounding completely out of touch seeing as I don’t have kids.
What I can do is show you a layout for a bathroom that the kids share. They each get their own sink, and there is still privacy in the toilet area in case one absolutely can not wait for the other to finish using the bathroom before needing to brush their teeth…or wash their hands…or floss (see? I have no idea what kids do).
I hope this layout gives you some inspiration for your future dream home!